Process of making metallic soaps



Patented Sept. 10, 1935 UNITED STATES that? PROCESS OF MAKING METALLICSOAPS corporation of Ohio No Drawing. Application January 9, 1932,Serial No. 585,800

18 Claims.

This invention relates to the process of making metallic soaps and moreparticularly to the heavy metal soaps of the drying oil acids,especially tung oil, and has for its object the covering of theparticles of the soap with a protective film to prevent oxidation.

The water insoluble heavy metal soaps are used both as driers and astransparent pigments for the manufacture of fiat varnishes and lacquersand for such purpose must be finely divided pale colored powders, whichpermit of easy grinding in lacquer or varnish vehicles. The zinc,calcium, aluminum and magnesium soaps of the fatty acids are commonlyutilized; these are manufactured by precipitation of sodium soapsolutions by soluble heavy metal salt solutions, followed by filtration,washing, and drying.

The soaps commonly employed in the past have been those of fatty acidswhich are completely 20 saturated, or nearly sostearic, palmitic, etc.The soaps of thesesalts may be dried without difficulty and yield finewhite powders. Recently, however, the use of soaps of the drying acidshas been suggested and adopted because of their waterproof qualities.These soaps have lower melting points, however, than the soaps of thesaturated acids and cannot be dried at elevated temperatures withoutdanger of fusion. Furthermore, the unsaturated acids absorb oxygen from30 the air during the drying period, causing darkening. Where masses ofthese soaps are stored, oxidation causes heating, which may result infusion in the container.

Of the drying oil soaps, the tungates are the most outstanding becauseof their waterproofness. But because wood oil is the most rapid dryingof all the oils, the technique of handling the wood oil soaps is mostdiflicult. This is especially noticeable in the zinc soap, as zinc has adrying action on oils, while the other heavy metals used for pigmentsoaps do not. As a result of this combination of drier radical withrapid oxidizing radical, zinc tungate cannot be handled in the drystate. When the fresh press cake is spread out to dry, a heat of over100 F. is fatal, as the material fuses long before the water is gone. Ifa thin layer is spread out at room temperature and dried by aircirculation, reasonably good results can be obtained, although thetungate darkens; but the resultant dry zinc tungate, stored incontainers, fuses spontaneously, and We have often noted that it willcatch fire while so doing. Immediate wetting with organic liquids andgrinding does not always help because small agglomerates have beenfused, and the resultant pigment paste contains these agglomerates,which must then be centrifuged out of the fiat varnish or lacquer.Because of these difficulties, zinc tungate pigment cannot be purchasedin the open market. 5

Because of the extremely valuable properties of zinc tungate as aflattening pigment and its absence from the open market for the reasonsstated, we endeavored to find some way of preparing this product inavailable form for storage and shipment from plant to plant.

We found that dry zinc tungate may be prepared and stored by adding tothe wet slurry approximately 1% of a sugar, based on the Weight of dryzinc tungate. The sugar apparently forms a protective film over theparticles, and prevents oxidation of the interiorpigment particle. Anysugar will Work, but we prefer to use glucose because of its low cost.

In a preferred form of our invention, we sapon- China wood oil 40 lbs.

Flake caustic soda 6 lbs. Water 9 gals.

by heating just short of boiling for 2-8 hours until saponification iscomplete. The soap is added :to a solution of 17 pounds of commercialzinc sulphate in 10 gallons of water, slowly, and with constantagitation. To the resultant slurry, a solution of pound of glucose inWater is then added, and stirred thoroughly. The slurry is then filteredthrough a press or centrifuge. The press cake is spread on racks to dryat approximately 110 F. and is then stored.

We have varied the methods of saponification and precipitation and haveeven dried up to 140 F. without fusion. Above this temperature, however,fusion is apt to take place.

Sucrose and other common sugars give results comparable with glucose,but are more expensive. We prefer to hold the sugar to a minimum. While1% of sugar does not affect the waterproofness and general desirabilityof the zinc tungate as a fiatting pigment, higher amounts have atendency to do so. We use a minimum of sugar that will prevent fusion.

Other tungates and drying oil soaps in general may be kept fromoxidizing by this method; but our experience indicates that those thatremain solids at normal temperatures can be prepared without the use ofsugar by careful manipulation. However, the addition of sugar gives awider latitude in plant operating conditions.

We claim:

1. The process of producing a stable dry zinc tungate consisting ofprecipitating the soap by any of the known methods, adding one percentof sugar, separating the soap and drying.

2. The process of producing a stable dry zinc tungate consisting ofprecipitating the soap by any of the known methods, adding one percentof glucose, separating and drying.

3. The process of producing a stable dry zinc tungate consisting ofpreciptiating the soap by any of the known methods, adding sugar insufficient quantity to prevent fusion and oxidation of the soap upondrying but insufiicient to aifect the waterproofness of the soap.

4. The process of producing a stable dry zinc tungate consisting ofprecipitating the soap by any of the known methods, adding glucose insufficient quantity to prevent fusion and oxidation of the soap upondrying but insufficient to affect the waterproofness of the soap.

5. The process of producing a stable dry zinc tungate consisting ofcoating the particles of the tungate-with a protective film of sugarsuflicient to prevent fusion and oxidation or the soap upon drying butinsufiicient to affect the waterproofness of the soap.

6. The process of producing a stable dry zinc tungate consisting ofcoating the particles of the tungate with a protective film of glucosesufficient to prevent fusion and oxidation of the soap upon drying butinsufiicient to aifect the waterproofness of the soap.

'7. A powdered zinc tungate the particles of which are coated with asugar in sufficient quantity to prevent fusion and oxidation of the soapupon drying but insufficient to afiect the Waterproofness of the soap.

8. A powdered zinc tungate the particles of which are coated withglucose sufficient to prevent fusion and oxidation of the soap upondrying but insuflicient to aifect the waterproofness of the soap.

9. A powdered tungate the particles of which are coated with a sugarsuificient to prevent fusion and oxidation of the soap upon drying butinsufficient to affect the waterproofness of the soap.

.of the soap.

10. A powdered tungate the particles of which are coated with glucosesufiicient to prevent fusion and oxidation of the soap upon drying butinsufficient to afiect the waterproofness of the soap. 5

11. A powdered drying oil soap the particles of which are coated with asugar which will prevent fusion and oxidation of the soap upon dryingbut insuificient to affect the'waterproofness of the soap.

12. A powdered drying oil soap the particles of which are coated withglucose which will prevent fusion and oxidation of the soap upon dryingbut insuflicient to affect the waterproofness V V W r 7.

13. The process of making a stable zinc tungate which consists of addingto the soap a water solution of sufiicient sugar to coat the particlesof soap, and separating the soap from the liquid.

14. The process of making a stable zinc tungate Which'consists of addingto the soap a Water solution of sufficient glucose to coat the particlesof soap, and separating the soap from the liquid.

15. The process of making a stable tungate which consists of adding tothe soap a water solution of suiiicient sugar to coat the particles ofsoap, and separating the soap from the liquid.

16. The process of making a stable tungate which consists of adding tothe soap a water solution of sufficient glucose to coat the particles ofsoap, and separating the soap from the liquid.

17. The process of making a stable drying oil soap which consists ofadding to the soap a water solution of sufficient sugar to coat theparticles of soap, and separatingthe soap from the liquid.

18. The process of making a stable drying oil soap which consists ofadding to the soap a water solution of sufficient glucose to coat theparticles of soap, and separating the soap from the liquid.

WILLIAM J. OBRIEN. GORDON H. MUTERSBAUGH.

